In the modern commercial and military airplane auxiliary fuel tank system, the fuel tank storage volume or the number of the fuel tanks will be adjusted according to the distance of the destination for the purpose of the saving fuel and increasing fuel usage efficiency. Transfer tubes are used to connect the auxiliary fuel tanks of commercial and military airplanes, and to transfer the fuel from one tank to another during flight. The use of traditional connection methods such as tubing, hose, and bellows is constrained due to the limited connection space between the tanks, the large diameter of the flow passage, and the large radial and axial movements caused by the manufacturing tolerances of the fuel tank equipment and the dynamic environment during the flight.
Traditional connection methods are simply not capable of meeting the function, safety, and reliability requirements with a large pressure surge and a constant large cyclic radial and axial motion within a small space. It would therefore be a significant advantage over the prior art to overcome the limitations of the prior art and to endure the harsh environment of modern commercial and military airplane auxiliary fuel tank systems.